Involute flat tube and plate fin radiator



Nov. 20, 1962 J. A. MONAB 3,064,947

INVOLUTE FLAT TUBE AND PLATE FIN RADIATOR Filed Feb. 20, 1959 4 Sheets-Sheet l 52220 JOHN AMcNAB D B) EDWARD C. W VNNE, ADM INIS TRATOR ATTORNEY Nov. 20, 1962 J. A. MCNAB 3,064,947

INVOLUTE FLAT TUBE AND PLATE FIN RADIATOR Filed Feb. 20, 1959 F/G. Z

4 Sheets-Sheet 2 INVENTOR JOHN AMcNAB, DECEASED BY EDWARD C. W VNNE, ADMINISTRATOR gy fi W ATTORNEY Nov. 20, 1962 J. A. MONAB 3,064,947

INVOLUTE FLAT TUBE AND PLATE FIN RADIATOR Filed Feb. 20, 1959 4 Sheets-Sheet 5 JOHN A. McNAB, DECEASED BY EDWARD C. WYNNE, ADMINISTRATOR ATTORNEY Nov. 20, 1962 J. A. MONAB 3,064,947

INVOLUTE FLAT TUBE AND PLATE FIN RADIATOR Filed Feb. 20, 1959 1 4 Sheets-Sheet 4 5 IN VEN TOR a JOHN A. McNAB, azcusso BY EDWARD c. wy/v/ve; ADMINISTRATOR A T TORNEV nited States Patent Ofiiice 3,054,947 Patented Nov. 20, 1962 3.064,947 INVQLUTE FLAT TUBE AND PLATE FIN RADIATOR John A. McNab, deceased, late of Glastonbury, (Tenn,

by Edward C. Wynne, administrator, Glastonbury,

(Ionm, assignor to United Aircraft Corporation, a corporation of Delaware Filed Feb. 20, 1959, Ser. No. 794,764 9 Claims. (Cl. 257-235) This invention relates to heat exchangers and in particular to a liquid-metal-to-air radiator for use in nuclear powered gas turbine engines.

It is an object of this invention to provide an improved radiator suitable for installation between the shaft connected compressor and turbine sections of such an engine.

Another object of this invention is to provide an improved uniform matrix of involute tubes in the annulus formed between inner and outer annular shells of such a radiator.

A further object of this invention is to provide an improved header construction for such a radiator resulting in improved flow distribution and decreased pressure losses in the liquid metal streams flowing through the radiator.

A still further object of the invention is to provide improved fluid distribution for the liquid metal flow by the use of header bypass construction for both the inlet and outlet headers.

Another object of the invention is the provision of relatively hot and cold annular inlet and outlet headers located downstream and upstream, respectively, of the air stream and forming the outer shell of the radiator and a coaxial intermediate return header forming the inner shell of the radiator.

A further object of the invention is the provision of means for interconnecting the hot and cold headers which ailows for free radial and axial expansion thereof relative to each other.

A yet further object of the invention is generally to improve the construction and performance of radiators of this type.

These and other objects and advantages of the invention will be obvious or will be specifically pointed out in con nection with the following detailed description of one embodiment of the invention shown in the accompanying drawings.

in these drawings:

FIG. 1 is a perspective view with parts cut away showing the radiator of this invention;

PEG. 2 is an end view of FIG. 1 looking downstream;

EEG. 3 is a sectional view of line 33 of FIG. 2;

H6. 4 is a side elevation of the radiator as viewed from the right-hand side of PEG. 2;

FlG. 5 is a detail at the outlet of the inlet header bypass;

PIG. 5 is a detail at the inlet header elbow; and

FIG. 7 is a detail sectional view taken on line '77 of N6. 4.

The radiator of this invention provides a flow path for hot liquid metal which includes an outer cylindrical shell consisting of an upstream tubular outlet header 10 and a downstream tubular inlet header 12. This liquid metal flow path also includes an inner cylindrical shell consisting of a tubular intermediate, or return, header 14 which surrounds and is supported on a liner sleeve 16 through which the engine shaft is adapted to extend.

As shown in FIG. 2, the inlet header 12 has an inlet elbow 13 and the outlet header 10 has a similar outlet elbow 20, the inlet and outlet openings of which may face in any direction but herein face forward as shown in FIG. 1.

The headers are connected by a plurality of involute tubes 22 which are arranged in a plurality of staggered banks as will be evident in FIGS. 1 and 3, four banks being provided for each header. These tubes are arranged to efliciently fill the annulus between the inner and outer headers, the cylindrical walls 24, 26 of the outlet and inlet headers and the confronting wall 28 of the return header 14 comprising the tube sheets of the radiator. The counterflow path for the air discharged from the engine compressor is axially from left to right as viewed from FIG. 1 through the annulus occupied by tubes 22.

The radiator is supported on sleeve 16 by intermeshing centrally located splines 30 on the sleeve and 32 on header 14. At its outer periphery the radiator is supported on the engine outer casing (not shown) by annular splines which cooperate with external annular splines 34 and 35 on the outlet and inlet headers 10 and 12. This supporting structure for the radiator is shown more in detail and is claimed in a copending application of John A. McNah and John A. Olson, Serial No. 794,765, filed February 20, 1959.

Referring to the headers, and first to the inlet header 12, it will be noted that the header is generally rectangular in cross section, as shown in FIG. 3, and that this rectangular tubular passage is separated by a 'bafile 34a into two annular passages 36 and 38, and by a bafiie 46 into a semi-annular passage 4-2 which extends around the radiator from the inlet elbow 18. A barrier 43 is pro vided across passages 36 and 38 (FIG. 7) adjacent inlet elbow 18 to cause the incoming liquid metal to flow counterclockwise in these annular passages, as viewed in FIG. 2, so that the liquid metal can enter the involute tubes 22 without appreciable pressure lose due to fluid turning. By reference to FIG. 5, it will be noted that annular passages 36 and 38 are closed off by a partition 44 just prior to the point where the bypass passage 42 enters the main annular portion of the headers comprising passages 36 and 38. At the point at which the bypass enters the main header passages 36 and 33, the battle 34a is interrupted to provide a passage 46 between the annular passages 36 and 38 and a flow divider 48 is connected to the interrupted downstream end of bafl'le 34a and extends into semi-annular passage 42 to divide the flow in this passage between the roughly 180 portion of the passages 36 and 38 which extends from partition 44 back to barrier 43 adjacent the inlet 18.

The inlet elbow 18 has a flow divider 49 (FIG. 6), which directs half of the flow into passages 36 and 38 and the other half into passage 42, the flow into these passages 36 and 38 being proportioned by a further flow divider 50.

Barrier 34a is provided with a plurality of holes 52, as shown in FIG. 1, which assists in the distribution of the liquid metal flowing in passages 36 and 38. It will also be noted (FIG. 6) that turning vanes 54 are provided in the elbow of inlet pipe 18 which minimizes turbulence in the flow in the several passages.

From the above, it will be evident that fluid entering the inlet pipe 18 flows counterclockwise (FIG. 2) through passages 36 and 38, supplying the involute tubes 22 in the inlet header to a point approximately 180 from the inlet elbow 18 where these passages are closed off by barrier 44. The other half of the inlet flow, which has been diverted to the bypass passage 4-2, enters passages 36 and 38 just downstream of barrier 44 and supplies the involute tubes 22 for the remaining 180 of the inlet header.

The outlet header it? is similar to the inlet header except for its angular relationship, having two 360 passages 56 and 58 separated by a perforated baflie 6d, and a bypass passage 52 formed by the battle 64 which extends 180 around the header and picks up the How from the involute tubes discharging into annular passages 56 and 58 during the last 180 of these passages, a bafiie, not shown, being provided across passages '6 and 58 at the 180 point as was described in detail in connection with baflie 44 of the inlet header.

The intermediate, or return, header 14 receives the flow from all of the involute tubes 22 which are connected to the inlet header and discharges into the tubes connected to the outlet header. Thus, the header 14 conmeets the tubes of the inlet header to the tubes of the outlet header at the inner ends of the tubes, as is shown most clearly in FIG. 3. The fiuid flow in header lid is thus always in a forward direction.

The involute tubes 22 are arranged in a plurality of staggered banks of tubes, each bank extending 360 around the radiator. As shown in FIG. 3, four banks of tubes 22a, 22b, 22c and 22d are provided for the inlet header and four banks 22c, 22 22g and 22h for the outlet header. The tubes are flat and are bent in the flat direction so that they penetrate the inlet and outlet headers at such an angle that they reduce the turning loss in the fluid. Preferably, these tubes are provided with a plurality of fins which are perforated to receive two adjacent tubes in the same bank. These fins may be of copper with a stainless clad to give maximum heat conductivity together with corrosion resistance. The involute tubes are joined to the headers where they penetrate the header plate in a well-known manner by brazing or Welding;

Means are provided to permit relative expansion between the hot inlet header and the relatively cold outlet header; To this end, interrneshing radial face splines 4% are provided on the confronting surfaces of inlet and outlet headers ltl and 12, which provide support for the outer peripheries of the headers 1'3 and 7.2, while permitting radial and axial expansion between the two.

Drain pipes on and 69 are provided at the bottoms of the inlet and outlet headers, respectively, and drain holes 71 are provided in baflles 4-4 (FIG. 5) to avoid entrapment of the liquid metal. Drain passages 2 2 (FIG. 3) are also provided at the bottom edge of bafiies dd and 60 in the inlet and outlet headers. Similarly, flow divider 48 (FIG. 5) has drain passages 74 cut in its lower edge.

In the operation of the heat exchanger, air from the compressor is directed in an axial flow through the matrix comprising involute tubes 22 in the annular passage between the outer radiator shell comprising headers in and 12, and the inner radiator shell comprising the inner header 14. Liquid metal or other fluid from which heat is to be abstracted enters the inlet elbow is where it is divided into substantially equal streams by flow divider 49. One stream flows on one side of the divider, where it is further divided by flow divider 5-0 into equal streams which are directed into passages 36 and 33. The stream on the other side of flow divider 49 is directed into header bypass passage 42. The fluid which enters passages 36 and 3% flows around the inlet header through the first 180 of the header until it encounters barrier 44 (PEG. 5)

4 beyond which the header bypass passage 42 enters. The bypass fluid then flows around the remaining of the inlet header. Thus, in effect, the inlet header has two inlets supplying it at locations 180 apart.

Fluid from the inlet header passages 36 and 38 flows through the banks 22a, 22:), 22c and 22d of involute tubes 22 into the return header 1.4, flows forward along this header, and enters passages 56 and 58 of the outlet header 10. Of the fluid which enters the passages 56 and 53 of the outlet header it} that from the first half of the circumference of passages 56 and 53 is discharged through the passage 7% on one side of the how divider "K in the outlet elbow 2%. (FIG. 1). The other half is discharged through the header bypass passage 62 which connects with the passage '78 on the other side of the how divider 76 in the outlet elbow. It will thus be evident that the flow of fluid through the inlet header is identical to that through the outlet header except for the direction of flow.

From the above description it will be evident that a radiator has been provided which has definite advantages for a liquid metal-to-air radiator for use in gas turbine engines.

it will also be evident that a particularly simple but effective flow path for the liquid metal has been provided including an improved and simplified header construction and involute tube matrix in which the tubes penetrate the inlet and outlet headers so as to reduce the turning losses.

Further, it will be evident that by the provision of the header bypass construction, which takes some of the liquid metal entering the inlet elbow, for example, and introduces it into the inlet header at a point 180 advanced from the inlet elbow, the effect. is produced of feeding the header from two different sources.

These advantageous features will be evident together with the improved means for supporting the relatively hot and cold headers while allowing for expansion and contraction in both the axial and radial direction and the improved tube and fin construction which provides a maxi mum of heat transfer while presenting a rigid and vibration-free tube and fin matrix.

While only one embodiment of the invention has been shown and described, it will be understood that various changes are possible in the construction and arrangement of the various parts of the radiator within the scope of the invention.

What is claimed is:

1. In a fluid heat exchange device, annular inlet and outlet headers arranged side-by-side and forming the outer shell of the device, an inner return header concentric with said inlet and outlet headers and forming the inner shell of the device, the annular space between said shells defining an axial fluid passage through the device, a plurality of pipes connecting said inlet and outlet headers with said return header, means for introducing fluid to said inlet leader at two circumferentially spaced points including an inlet pipe communicating with said inlet header, an inlet header bypass communicating with said inlet pipe at one end and communicating with said inlet header at its other end at a point circumferentially spaced from said inlet pipe, and flow divider means for directing part of the flow in said inlet pipe to said inlet header bypass.

2. In a fluid heat exchange device, annular inlet and outlet headers arranged side-by-side and forming the outer shell of the device, an inner return header concentric with said inlet and outlet headers and forming the inner shell of the device, the annular space between said shells defining an axial fluid passage through the device, a plurality of pipes connecting said inlet and outlet headers with said return header, means for introducing fluid to said inlet header at two circumferentially spaced points including an inlet pipe communicating with said inlet header, an inlet header bypass communicating with said inlet pipe at one end and communicating with said inlet header at its other end at a point circumferentially Spaced from said inlet pipe, flow divider means for directing part of the flow in said inlet pipe to said inlet header bypass, means for discharging fluid from said outlet header at two circumferentially spaced points including an outlet pipe communicating with said outlet header, an outlet header bypass communicating with said outlet pipe at one end and communicating with said outlet header at its other end at a point circumferentially spaced from said outlet pipe, and flow divider mean for directing part of the flow in said outlet header to said outlet header ass.

In a fluid heat exchange device, annular inlet and outlet headers arranged side-by-side and forming the outer shell of the device, an inner return header concentric with said inlet and outlet headers and forming the inner shell of the device, the annular space between said shells defining an axial fluid passage through the dev1ce, a plurality of pipes in said annular space connecting said inlet and outlet headers with said return header, rneans for introducing fluid to said inlet header at two circumferentially spaced points including an inlet PIPE communicating with said inlet header, an inlet header bypass communicating with said inlet pipe at one end and communicating with said inlet header at its other end at a point circumferentially spaced from Said inlet pipe, flow divider means for directing part of the flow in said inlet pipe to said inlet header bypass, means for discharging fluid from said outlet header at two circumferentially spaced points including an outlet pipe communicating with said outlet header, an outlet header bypass communicating with said outlet pipe at one end and com municating with said outlet header at its other end at a point circumterentially spaced from said inlet pipe, flow divider means for directing part of the flow in said outlet header to said outlet header bypass, and barrier means for closing ofl said inlet and outlet headers at the entrance and exit respectively of said bypass flows.

4. In a fluid heat exchange device, an annular inlet header, a parallel annular outlet header, said inlet and outlet headers constituting the outer shell of the device, a concentric annular header constituting the inner shell of the device, the confronting surfaces of said inner and outer headers constituting the header tube sheets, a tube matrix in the annular space between said inner and outer headers, a fluid inlet connection to said inlet header, barrier means for closing ofl said inlet header approximately 180 from said inlet connection, an inlet header bypass extending from said fluid inlet connection and communicating with said inlet header beyond said barrier means, a fluid outlet connection from said outlet header, barrier means for closing off said outlet header approximately 180 from said outlet connection, and an outlet header bypass extending from said outlet header on the outlet side of said barrier and communicating with said fluid outlet connection.

5. In a fluid heat exchange device, an annular inlet header, a parallel annular outlet header, said inlet and outlet headers constituting the outer shell of the device, an inner annular return header constituting the inner shell of the device, the confronting surfaces of said inner and outer headers forming header tube sheets, a plurality of tubes located in the annular space between said inner and outer shells having their opposite ends penetrating said tube sheets, a single inlet connection to said inlet header, a single outlet connection to said outlet header, an inlet header bypass communicating with said inlet header connection at one end and connected at its other end with said inlet header at a point remote from said inlet header connection for introducing fluid to said inlet header at said remote point, an outlet header bypass communicating with said outlet header connection at one end and connected at its other end with said outlet header at a point remote from said outlet header connection for discharging fluid from said outlet header at said remote point.

6. In a heat exchange device, an annular inlet header, a parallel annular outlet header, said inlet and outlet headers constituting the outer shell of the device, an in ner annular header constituting the inner shell of the device, the confronting surfaces of said inner and outer headers forming the header tube sheets, a. plurality of tubes located in the annular space between said inner header and said inlet and outlet headers having their opposite ends penetrating said tube sheets, a single inlet connection to said inlet header, a single outlet connection to said outlet header, an inlet header bypass communicating with said inlet connection and connected with said inlet :header at a point remote from said inlet connection for introducing fluid to said inlet header at said remote point, an outlet header bypass communicating with said outlet connection and connected with said outlet header at a point remote from said outlet connection for discharging fluid from said outlet header at said remote point, and baflie means in said inlet and outlet headers for proportioning the flow to said bypass and annular passages of said headers.

7. In a fluid heat exchange device, annular inlet and outlet headers arranged side-by-side and forming the outer shell of the device, an inner return header concentric with said inlet and outlet headers and forming the inner shell of the device, the annular space between said shells defining a passage for one of the fluids, a plurality of involute tubes arranged in staggered banks in said annular space for connecting said return header to said inlet and outlet headers, said inlet and outlet headers having perforated annular partitions which divide them into two annular passages, an inlet header connection for supplying fluid to said two annular passages of said inlet header, and a semi-annular inlet bypass passage receiving fluid from said inlet header connection at one of its ends and discharging into said two annular passages of said inlet header at its other end, said annular inlet passages having a barrier thereacross upstream of the discharge from said inlet bypass passage.

8, In a fluid heat exchange device, annular inlet and outlet headers arranged side-by-side and forming the outer shell of the device, an inner return header concentric with said inlet and outlet headers and forming the inner shell of the device, the annular space between said shells defining a passage for one of the fluids, a plurality of involute tubes arranged in staggered banks in said annular space for connecting said headers, both said inlet and outlet headers having perforated annular partitions which divide each of them into two annular passages, an inlet header connection for supplying fluid to said two annular passages of said inlet header, a semi-annular inlet bypass passage receiving fluid from said inlet header connection at one of its ends and discharging into said two annular I passages of said inlet header at its other end, said annular inlet passages having a barrier thereacross upstream of the discharge from said inlet bypass passage, and a semi.- annular bypass passage receiving fluid from said two annular passages of said outlet header at one end and discharging into said outlet header connection at its other end, said annular outlet passages having a barrier there across upstream of the inlet to said outlet bypass passage,

9. A drum-shaped heat exchanger having a two-part outer hollow cylindrical shell and a concentric inner hols low cylindrical shell forming an annulus therebetween defining an axial flow passage for one fluid to pass through the exchanger, said outer shell comprising an annular upstream outlet header forming one-half of the outer shell and an annular downstream inlet header forming the other half of said outer shell, a single fluid inlet and a single outlet connection to said inlet and outlet headers respectively, a bank of tubes in said annulus connecting the up stream end of said inner shell with said outlet header, a second bank of tubes in said annulus connecting the downstream end of said inner shell with said inlet header,

municating at one end With said inlet header approximately halfway around said annular inlet header from said inlet connection and receiving fluid at its other end from said fluid inlet connection, and said outlet header having a bypass conduit communicating at one end With said outlet header approximately halfway around said outlet header from said outlet connection and discharging fluid at its other end into said fluid outlet connection.

References fitted in the file of this patent UNITED STATES PATENTS Lysholtn June 20, 1939 Arvins et al Oct. 10, 1944 Henstridge Aug. 16, 1949' Buckland' Apr. 3, 1951 Cowlin et al. Apr. 1,- 1958 Clark Jan.'20,-1959 Cornyns-Carr Jan. 27, 1959 Halford et al. Apr. 7, 1959 FOREIGN PATENTS Great Britain Dec. 10, 1958 UNITED STATES PATENT OFFICE CERTIFICATE OF CoRRECTIoN Patent No. 3,064,947 November 20, 1962 John A, McNab, deceased, by Edward c, Wynne, administrator It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 34, for "inlet" read outlet Signed and sealed this 30th day of April 1963;

(SEAL) Attest:

RNEST w. SWIDER DAVID A D Attesting Officer Commissioner of Patents 

